This invention relates generally to human powered vehicles and more specifically to four wheel, two person, human powered vehicles.
The history of land based human powered vehicles is relatively short. The first pedal driven bicycles were invented in the mid 1800's. Since that time, land based human powered vehicles have been continually improved, redesigned, modified, and adapted to many uses.
Efficiency has been an important consideration in the design of human powered vehicles. The human body is capable of producing only a fraction of one horse power for any sustained length of time and thus any waste of this energy greatly affects the performance and usefulness of a human powered vehicle.
To improve efficiency, human powered vehicles have become lighter and multi-speed gearing has been added. The frames, wheels, bearings, and tires have all been improved to increase efficiency. Even the position of the operator has been changed to reduce wind resistance and improve human body efficiency.
The most popular of human powered vehicles are bicycles. Bicycles, however, are very unstable by design. At low speeds they tend to fall over. At higher speeds, an unexpected bump, turn, or obstacle can cause the bicycle to crash. If more than one person is to ride on a bicycle they must ride in tandem. The tandem configuration is even more unstable and requires much skill and practice to ride safely.
For these reasons, and others, three and four wheeled human powered vehicles have been developed.
Three and four wheeled human powered vehicles are well known in the art. However, prior designs are all deficient in one or more respects. Examples of patented three and four wheeled vehicles are:
U.S. Pat. No. 4,826,190, entitled "Dual Wheel Driven Tricycle With A Fully Enclosed Multiple Speed Drive" issued to Hartmann on May 2, 1989 shows a single seat tricycle with a multi-speed transmission. This vehicle does not have four wheels, carries only a single operator, does not have any suspension, uses a complex transmission mechanism and does not have a single control for independently controlling the braking applied to each rear wheel. This vehicle's freewheels for dual wheel drive are mounted on heavier load bearing axles at each rear wheel.
U.S. Pat. No. 4,070,032, entitled "Four Wheel Pedal Driven Vehicle" issued to Cunningham on Jan. 24, 1978 shows a four wheel tandem vehicle. This vehicle does not have an independent drive train for each operator nor does it allow each operator to use a different gear ratio. It drives only one rear wheel in the forward speed and has no substantial suspension system.
U.S. Pat. No. 4,9663,381 entitled "Adult Tricycle" issued to Feikema on Oct. 30, 1990 shows a one person tricycle. This vehicle does not have four wheels, only drives a single rear wheel, has room for only one operator, and has no suspension system.
U.S. Pat. No. 4,674,762 entitled "Four-Wheel, Reclining Position Cycle" issued to Nelson et al. on Jun. 23, 1987 shows a one person four wheel human powered vehicle This vehicle only seats one operator, drives only one rear wheel, has no suspension, and does not provide for controlling the rear brakes independently.
U.S. Pat. No. 4,792,149 entitled "Pedal-Powered Golf Cart" issued to Harmon on Dec. 20, 1988 shows a three wheel two person human powered vehicle. This vehicle uses a transmission box, a drive shaft, and differential joint. The drawbacks of this vehicle are that it is specifically adapted for use on a golf course or the like. It is not designed for high speeds, does not provide independent gearing for each operator, and has very limited suspension.
U.S. Pat. No. 4,093,258 entitled "Multipassenger Pedal vehicle" issued to Ansel on Jun. 6, 1978 shows a multi-passenger vehicle with three, four or more wheels. This vehicle only allows an operator to drive a single rear wheel. It is a tricycle like configuration which is inherently unstable, and does not have any suspension.
U.S. Pat. No. 4,925,200 entitled "Tricycle Drive Mechanism" issued to Jones on May 15, 1990 shows a single passenger tricycle. This vehicle uses a push-pull type drive mechanism instead of a cranking foot pedal. The operator uses both his arms and his legs to propel the vehicle. This vehicle only allows one operator, does not have multiple gearing and has no suspension.
Clearly, there exists a need for an improved four wheel human powered vehicle which is stable, efficient, seats multiple operators and is usable both on and off road.